Question no 68

# Doubt from parabola

Answer is equals 4.

Answer is 8 given in answer key

since vertex is shifted in a line parallel to x=y

therefore ,let the new vertex be (a,4+a) with "a" being a simple parameter

since no other change is made to the parabola

substitute y=y-a and x=x-a

and we know one of the root to be +2 substitute in parabola eqn to get "a"

the find the other root to get the answer

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answer is 8. Vertex will become of form (h,h+4). So parabola can be written as (x-h)^2=(h+4-y). Now put B(2,0) in eqn and h will come out to be 5.

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